Cisco 4507 IOS upgrade stopped TFTP communication for Avaya 4625 phone

[ds00476784@techmahindra.com]

#Help 

I have recently upgraded our cisco 4507 switches from IOS "Cisco IOS XE Release 3.8.6E".

to " Cisco IOS XE Release 3.11.6E".

After upgrade Avaya 4625 and Avaya 9600 series phones stoped reaching TFTP and utility servers. 

There is no config changes. No firewall in between. 

Tftp server working properly for voice vlan. Problem only been faced with phones connected switches where IOS was upgrade d. 

Packet capture didn't helped. Line by line config checked before and after no difference. 

for testing we rolled back IOS on one of switche and phones started working. 

Cisco Tac is unable to find problem yet. 

I do not want to roll back as I have done it for many switches. 

Problem was identified when phones rebooted randomly and they were unable to download config from tftp server. 

802.1x configured on ports and they are Successfully passing authentication. 

[balaji.bandi]

how is your Layer 3 Interface config, how is your Layer 2 switch port config?

From Layer3 are you able to reach TFTP ? how is TFTP config pushed from DHCP ?

[ds00476784@techmahindra.com]

Layer 3 and layer 2 are good. We can download file manually if we connect a laptop with TFTP client.

Only Phones are not able to down config files. Issue resolved we downgrade the IOS.

No config change at any stage was done. 

[balaji.bandi]

how is your Layer 3 Interface config, how is your Layer 2 switch port config?

From Layer3 are you able to reach TFTP ? how is TFTP config pushed from DHCP ?

Still, I do not see the input that we asked here to understand the issue. we do understand downgrade works ?

Can you post an example config here? and explain how TFTP is configured to get the config to Phone ? from DHCP ?

[ds00476784@techmahindra.com]

layer 3 for Voice vlan is on Distribution sw. Access sw have Layer 2 vlan and passed over trunk link.

From Layer 3 we are able to reach TFTP. If we assign a laptop with Ip from voice vlan on same access switch we can download file using tftp client manualy.

TFTP Ip is configured in Phones. i will check and share config 

[Leo Laohoo]

Downgrade to 3.11.5.

[ds00476784@techmahindra.com]

Do you know the problem or experienced same. Can you share some more insights.

[Leo Laohoo]

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ds00476784@techmahindra.com wrote:
Do you know the problem or experienced same. Can you share some more insights.

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Downgrade to 3.8.5.  If the issue goes away, then it is a bug.